The objective of this proposal is to develop and improve endoscopic-compatible spectroscopic techniques based on excitation-emission matrix (EEM) fluorescence, reflectance and light scattering for real-time in vivo analysis and diagnosis of dysplasia in the colon, esophagus and urinary bladder. We have developed three models to analyze tissue reflectance and fluorescence. The diffuse reflectance model furnishes information about tissue scatterers (such as mitochondria and the fiber network of connective tissue) and absorbers (such as hemoglobin). The light scattering spectroscopy (LSS) model yields information about nuclear size and crowding in the epithelial layer of tissue. The intrinsic fluorescence model isolates the contributions of fluorophores (such as structural proteins, NADH, porphyrins etc.) from the interference of absorbers and scatterers. Clinical EEM fluorescence/reflectance data will be collected for colonic adenoma, Barrett's esophagus and urothelial carcinoma, and will be analyzed using these models. Information about tissue structure and composition will be extracted and used to formulate new models and diagnostic algorithms. Validation of the algorithms will be performed prospectively with extended clinical data sets. In addition, we will extend the excitation wavelength range of our clinical EEM system down to 308 nm, to access more information about epithelial cellular proteins, update our data acquisition systems, and integrate data analysis software for real-time diagnosis.